Polyglutamine expansion in Drosophila: thermal stress and Hsp70 as selective agents

Bettencourt, Brian R.; Hogan, Catherine; Nimali, Mario

doi:10.1007/s12038-007-0053-9

Cited by 18 publications

(21 citation statements)

References 57 publications

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“…Polyglutamines (PolyQs) are the most frequent type of homoamino acid tracts found in the Drosophila melanogaster proteome (Bettencourt et al , 2007 ). At least 30 Drosophila proteins possess polyQ tracts of 20 residues or longer, which are conserved in other drosophilid species.…”

Section: Introductionmentioning

confidence: 99%

“…Screening of the Saccharomyces cerevisiae protein database ( www.yeastgenome.org ) revealed that polyQ tracts are the most common homopolymeric amino acid tracts of eight amino acids length or longer. Functional association analysis showed that the most prevalent triplet repeats found in human ORFs (CGG coding for alanine; CAG, glutamine; CCG, proline; AGG, glutamic acid; ACC, histidine) predominantly occur in genes associated with transcription-related functions (Bettencourt et al , 2007 ). For example, transcriptional regulators such as Snf5 and Gal11 in S. cerevisiae , prospero and dClock in Drosophila , and TATA box-binding protein (TBP), forkhead box protein P2 (FoxP2), and the androgen receptor in humans contain polyQ tracts of at least 20 residues.…”

Section: Introductionmentioning

confidence: 99%

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Polyglutamine tracts as modulators of transcriptional activation from yeast to mammals

Atanesyan¹,

Günther

Dichtl

et al. 2012

Biological Chemistry

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Microsatellite repeats are genetically unstable and subject to expansion and shrinkage. A subset of them, triplet repeats, can occur within the coding region and specify homomeric tracts of amino acids. Polyglutamine (polyQ) tracts are enriched in eukaryotic regulatory proteins, notably transcription factors, and we had shown before that they can contribute to transcriptional activation in mammalian cells. Here we generalize this fi nding by also including evolutionarily divergent organisms, namely, Drosophila and baker ' s yeast. In all three systems, Gal4-based model transcription factors were more active if they harbored a polyQ tract, and the activity depended on the length of the tract. By contrast, a polyserine tract was inactive. PolyQs acted from either an internal or a C-terminal position, thus ruling out a merely structural ' linker ' effect. Finally, a two-hybrid assay in mammalian cells showed that polyQ tracts can interact with each other, supporting the concept that a polyQ-containing transcription factor can recruit other factors with polyQ tracts or glutamine-rich activation domains. The widespread occurrence of polyQ repeats in regu latory proteins suggests a benefi cial role; in addition to the contribution to transcriptional activity, their genetic instability might help a species to adapt to changing environmental conditions in a potentially reversible manner.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Polyglutamine tracts as modulators of transcriptional activation from yeast to mammals

Atanesyan¹,

Günther

Dichtl

et al. 2012

Biological Chemistry

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“…To validate whether these selected reference genes are reliable in the conditions tested in this study, the expression levels of HSP70, an important stressinducible heat shock protein gene (Bettencourt et al 2007) and AfatCYP71D7, a P450 gene that could be induced significantly by herbicides in our previous results, were analysed in different developmental stages, tissues, and herbicide treatments, demonstrating that the use of unsuitable reference gene for normalisation might lead to deviated results. Therefore, it has proved that choosing appropriate reference genes for normalisation is a key precondition for the accurate estimation of target gene expression though only two target genes were chosen to validate these selected reference genes.…”

Section: Discussionmentioning

confidence: 94%

Selection and evaluation of potential reference genes for gene expression analysis in Avena fatua

Liu¹,

Li²,

Lu³

et al. 2019

Plant Prot. Sci.

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Citation: Liu J., Li P., Lu L., Xie L., Chen X., Zhang B. (2019): Selection and evaluation of potential reference genes for gene expression analysis in Avena fatua. Plant Protect. Sci., 55: 61-71.Abstract: Eight commonly used candidate reference genes, 18S ribosomal RNA (rRNA) (18S), 28S rRNA (28S), actin (ACT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), elongation factor 1 alpha (EF1α), ribosomal protein L7 (RPL7), Alpha-tubulin (α-TUB), and TATA box binding protein-associated factor (TBP), were evaluated under various experimental conditions to assess their suitability in different developmental stages, tissues and herbicide treatments in Avena fatua. The results indicated the most suitable reference genes for the different experimental conditions. For developmental stages, 28S and EF1α were the optimal reference genes, both EF1α and 28S were suitable for experiments of different tissues, whereas for herbicide treatments, GAPDH and ACT were suitable for normalizations of expression data. In addition, GAPDH and EF1α were the suitable reference genes.

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“…This proposition is based on the observation that trinucleotide repeats are common in eukaryotic DNA [19-21] and undergo mutation as a consequence of replication slippage more frequently than amino acid substitutions [11,22] but see [23]. Rather than being purged from the genome, long repeats are frequently conserved across vertebrates [19,24-27] and those containing glutamine or alanine tend to occur in transcription factors [28,29]. Contraction or expansion of a codon repeat in a transcription factor has the potential to modulate gene regulation in a quantitative, rather than qualitative, manner [10,30] and, therefore, result in a mutation of small effect [22].…”

Section: Introductionmentioning

confidence: 99%

Length polymorphism and head shape association among genes with polyglutamine repeats in the stalk-eyed fly, Teleopsis dalmanni

et al. 2010

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BackgroundPolymorphisms of single amino acid repeats (SARPs) are a potential source of genetic variation for rapidly evolving morphological traits. Here, we characterize variation in and test for an association between SARPs and head shape, a trait under strong sexual selection, in the stalk-eyed fly, Teleopsis dalmanni. Using an annotated expressed sequence tag database developed from eye-antennal imaginal disc tissues in T. dalmanni we identified 98 genes containing nine or more consecutive copies of a single amino acid. We then quantify variation in length and allelic diversity for 32 codon and 15 noncodon repeat regions in a large outbred population. We also assessed the frequency with which amino acid repeats are either gained or lost by identifying sequence similarities between T. dalmanni SARP loci and their orthologs in Drosophila melanogaster. Finally, to identify SARP containing genes that may influence head development we conducted a two-generation association study after assortatively mating for extreme relative eyespan.ResultsWe found that glutamine repeats occur more often than expected by amino acid abundance among 3,400 head development genes in T. dalmanni and D. melanogaster. Furthermore, glutamine repeats occur disproportionately in transcription factors. Loci with glutamine repeats exhibit heterozygosities and allelic diversities that do not differ from noncoding dinucleotide microsatellites, including greater variation among X-linked than autosomal regions. In the majority of cases, repeat tracts did not overlap between T. dalmanni and D. melanogaster indicating that large glutamine repeats are gained or lost frequently during Dipteran evolution. Analysis of covariance reveals a significant effect of parental genotype on mean progeny eyespan, with body length as a covariate, at six SARP loci [CG33692, ptip, band4.1 inhibitor LRP interactor, corto, 3531953:1, and ecdysone-induced protein 75B (Eip75B)]. Mixed model analysis of covariance using the eyespan of siblings segregating for repeat length variation confirms that significant genotype-phenotype associations exist for at least one sex at five of these loci and for one gene, CG33692, longer repeats were associated with longer relative eyespan in both sexes.ConclusionAmong genes expressed during head development in stalk-eyed flies, long codon repeats typically contain glutamine, occur in transcription factors and exhibit high levels of heterozygosity. Furthermore, the presence of significant associations within families between repeat length and head shape indicates that six genes, or genes linked to them, contribute genetic variation to the development of this extremely sexually dimorphic trait.

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Polyglutamine expansion in Drosophila: thermal stress and Hsp70 as selective agents

Cited by 18 publications

References 57 publications

Polyglutamine tracts as modulators of transcriptional activation from yeast to mammals

Polyglutamine tracts as modulators of transcriptional activation from yeast to mammals

Selection and evaluation of potential reference genes for gene expression analysis in Avena fatua

Length polymorphism and head shape association among genes with polyglutamine repeats in the stalk-eyed fly, Teleopsis dalmanni

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